The debate over where precisely is the dead centre of Great Britain is, quite literally, the centre of debate. Each day this week, we pinpoint the exact middles of Great Britain, England, Northern Ireland, Scotland and Wales.

The town of Haltwhistle has a claim to fame.

Bright red banners and colourful signs adorn the Northumberland town, proudly declaring it to be "The Centre of Britain".

However it is not the only town boasting the title, the main rival being Dunsop Bridge, Lancashire, 71 miles (114 km) away to the south.

The "true" centre is surrounded by peat bog

BBC News Online used co-ordinates calculated by the nation's chief mapping agency, the Ordnance Survey, to find the exact centre.

A global positioning system (GPS), which utilises satellites to find precise co-ordinates, was used in the search.

"As it is, only a few people visit the stones so they can say they went to the centre of Great Britain."

Mr Walker farms sheep and suckler cows on the 3,000-acre property, run by his family since 1970.

At nearby Dunsop Bridge - the nearest town to Brennand Farm - the only monument is a payphone.

Box marks the spot

BT installed its 100,000th payphone at the site in 1992 and included a plaque to explain its significance.

It reads: "You are calling from the BT payphone that marks the centre of Great Britain."

In fact, the phone is 4.2 miles (6.8 km) from the true centre.

Dunsop Bridge's monument is a payphone

Postmaster and shop owner Phil Woodhead said the town did not capitalise on its status.

"There is only that payphone really... we haven't put up big signs or anything like that," he said.

"If this was a bigger town with more shops, then maybe we would do something.

"But because we are so small, there is really no-one to push it."

Alternative view

But in Haltwhistle, David Taylor sees things differently.

He runs three businesses which use the name Centre of Britain - a hotel, laundrette and gallery.

He describes himself as an "amateur centrographer" and is passionate about the topic.

The symbolism of being at the centre appeals to the curious part of our minds

David Taylor

He finds the whole business with Dunsop Bridge "irritating" and refuses to believe the centre is anywhere but Haltwhistle.

The method used by the Ordnance Survey - known as the centre of gravity method - was "inappropriate" for Great Britain, he said.

To put it simply, the Ordnance Survey used a computer to find the point at which a cardboard cut-out of Great Britain would balance on a pinhead - its centre of gravity.

'Complicated' system

It is a technique widely recognised and used by many mapping agencies.

However Mr Taylor says this method is "incomprehensible" to most people.

He calculated the centre of Great Britain using six mathematical techniques and most of them gave the answer as Haltwhistle.

Centre of Britain Hotel was named in 1997

The main technique, which he says dates back to "ancient times", is finding the mid-point along Great Britain's longest line of longitude (which runs from the Orkney Islands in the north to Dorset in the south).

"The symbolism of being at the centre appeals to the curious part of our minds," he said.

Ordnance Survey spokesman Trevor Mouncey said the gravitational method was "the standard arithmetic principle of determining the centre of an irregular two-dimensional object".

"As such it has been used by everyone from Captain Cook to Nasa. It's a standard scientific application."

The basic problem is one of determining the centre of an irregular three-dimensional object on the surface of a sphere

Trevor MounceyOrdnance Survey

Mr Mouncey said the Ordnance Survey calculated the point at the request of a customer, but he did not understand why it generated such interest.

"As a cartographer, the centre of a land mass holds no romance or ethereal connotations as every cartographer and surveyor knows there is no such absolute," he said.

"I guess the less objective among us derive interest and intrigue from these points and I guess it might have something to do with the roll-out of scientific discovery over the last three centuries."

The location of Great Britain's true centre may never be entirely clear because of arguments over what method should be used to calculate it and the fact that Great Britain's shape changes with tides and erosion.

Furthest point

"The basic problem is one of determining the centre of an irregular three-dimensional object on the surface of a sphere," Mr Mouncey said.

"Not only that, but the 'irregular object' is surrounded by water which keeps moving about and is also responsible for changing the shape of the object on a daily basis."

It could be argued the centre of Britain is the furthest point from the sea.

The Ordnance Survey says this point lies just east of Church Flatts Farm, about a mile south-east of Coton in the Elms, Derbyshire.